I have the MA9, but it doesn't play high-res files above 48k unfortunately. It has been sitting rather idle lately.
A question or two to Mac users of the X5:
1. When I connect an X5 to iTunes, do I Copy-and-paste artist by artist or album by album?
2. Does anyone have experience with copying 300 GB of music in one go?
3. If I have two storage cards will the X5 automatically fill up one card first or must I decide where the files are copied to?
The next question is for all users. Does the X5 treat both cards as one storage file or do I need to decide which card to look at to find my music?
Now if only my iPod Classics can take more than 160 GB then I wouldn't need to consider this tempting X5.
The cards will show up separately in the Finder, similarly to an AK100. What I ended up using was Markspace Android software to copy files (and playlists, though they can't be used, yet) to the cards, since I can't fit my whole library on a card or cards. Likewise, this is going to replace an iPod Classic once playlist support is possible.
Before I forget: If you get a bunch of hidden files on a card (all starting with a period ".") you can nuke them with one of the tools in MacPilot that deletes Mac files in folders.
I've been listening with the X5 through a Pico Power with my Symphones Magnums and am getting similarly excellent results as I did with the AK100 and Pico Power. I think the battery was too low to power the Magnums directly as they didn't sound as good. I'll try again tomorrow once it has charged.